Simplify the following expression: $z = \dfrac{5a - 3}{4a - 9} \div \dfrac{1}{10}$
Answer: Dividing by a number is the same as multiplying by its inverse. $z = \dfrac{5a - 3}{4a - 9} \times \dfrac{10}{1}$ When multiplying fractions, we multiply the numerators and the denominators. $z = \dfrac{(5a - 3) \times 10} {(4a - 9) \times 1}$ $z = \dfrac{50a - 30}{4a - 9}$